Markowitz



March 17, 1964 J. MARKOWITZ 3,125,180

ELECTRO ACOUSTIC TRANSDUCER DEVICE Filed Sept. 17, 1962 3 Sheets-Sheet 1 TIE--lif 12 6 L, 5

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March 17, 1964 J. MARKOWITZ 3,125,180

ELECTRO ACOUSTIC TRANSDUCER DEVICE Filed Sept. 17, 1962 3 Sheets-Sheet 2 Z INVENTOR:

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March 17, 1964 J. MARKOWITZ 3,125,130

ELECTRO ACOUSTIC TRANSDUCER DEVICE Filed Sept. 17, 1962 3 Sheets-Sheet 3 Z1 j A B 2 INVENTCR:

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United States Patent 3,125,180 ELECTRO ACOUSTIC TRANSDUCER DEVICE Jerome Markowitz, Allentown, Pa., assignor to Allen Organ Company, Macungie, Pa., a corporation of Pennsylvania Filed Sept. 17, 1962, Ser. No. 223,899 13 Claims. (Cl. 181-27) This invention relates generally to devices which effect a change in the output sounds of loudspeakers, and more particularly concerns a unique electro acoustic transducer device which is adapted to be cooperatively associated with an electronic musical instrument such as an electronic organ, to develop sounds or tones of a special order.

Pipe organs are normally provided with a vox humana (human voice) stop which, when operated, will cause the organ to render special musical sound or tone effects having certain qualities or characteristics of the human voice. In an attempt to attain this same result with electronic organs, tremolo devices have heretofore provided for use with the latter, such as the tremolo device disclosed in U.S. Patent No. 2,062,515, which was issued December 1, 1936. However, such devices do not include, or embody, certain structural and functional features essential to the achievement of the said result in a manner that will establish comparative sound equality between the special pipe organ sounds and the similar electronic organ sounds to such an extent as to make the substitution of the latter for the former entirely acceptable and satisfactory to a professional or expert organist.

One object of my invention is to provide a electro acoustic transducer device which can be readily cooperatively associated with an electronic musical instrument such as an electronic organ, to thereby achieve the said special sound or tone results in the manner and to the extent indicated.

Another object is to provide such a device having certain structural and functional features of advantage over the prior art tremolo devices heretofore utilized for a similar purpose.

A further object is to provide such a device in the form of an electro acoustic transducer device which is actuated by the energy derived from an electronic musical instrument and the acoustic output of which is modulated by a mechano-acoustic arrangement.

An additional object is to provide such a device which can be initially combined with an electronic musical instrument so as to form an integral part thereof, or provided in the form of a separate unit for quick and easy combination with such an instrument as an attachment or auxiliary item.

It is also an object to provide such a device which structurally is comparatively simple and rugged and which in operation is highly effective and efiicient.

Another. feature of the invention resides in the pro vision of such a device which, when cooperatively associated with an electronic musical instrument such as an electronic organ, can achieve a muting effect, similar to that attained by a trumpet player when moving a derby toward and away from the end of his trumpet.

Another object is to provide such a device which comprises a loudspeaker, an air chamber structure arranged at the sound discharge end of the loudspeaker, a fan-like element rotatably mounted in said chamber, means for effecting rotation of said element, and adjustable means for determinedly establishing an opening of a certain order in said chamber, thereby to enable selective modulation of the acoustic characteristics of the sound emanating from said chamber.

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With these and other objects in view, which will become readily apparent from the following description of one practical and illustrative embodiment of my improvements shown in the accompanying drawings, my invention resides in the novel electro acoustic transducer device, elements, features of construction and arrangement of parts in cooperative relationship as more particularly indicated and defined by the hereto appended claims.

In the drawings:

FIGURE 1 is a top view of one form of electro acoustic transducer device in accordance with my invention;

FIG. 2 is a front elevational view of the device shown in FIG. 1;

FIG. 3 is a detail elevational sectional view, taken substantially as indicated by the arrow 3-3 on FIG. 1;

FIG. 4 is a horizontal sectional view, on an enlarged scale, taken substantially as indicated by the arrows 4-4 on FIG. 2, certain parts being bro-ken away so as todisclose structural details;

FIG. 5 is an elevational sectional view, of the same scale as FIG. 4, taken substantially as indicated by the arrows 5-5 on FIG. 1; and

FIG. 6 is a top view, similar to BIG. 1, but of a modified form of my electro acoustic transducer device which embodies a novel muting feature and some of the parts of which are more or less diagrammatically or schematically indicated.

The electro acoustic transducer device of my invention may be located at any suitable place in cooperative association with an electronic musical instrument and connected with the latter in the usual manner of a loudspeaker device. For example, when associated with an electronic organ, it may be located on top of, along the side, or at the back of the console, or at some other place where the device will perform its intended function in a practical manner.

In the accompanying drawings, the device is shown in a form particularly designed for cooperative association with an electronic organ of a conventional type, such, for example, as those manufactured and sold by the Allen Organ Company of Macungie, Pennsylvania. From this disclosure, it will be readily apparent to those skilled in this art how the device may be made and associated, in similar manner, with other types of electronic musical instruments and the like. Accordingly, it is to be understood that my invention is not limited in its use to the field of electronic organs, but that it may be similarly combined with other electronic musical instruments and the like, to accomplish the same new and beneficial re sults.

Referring first to FIGS. 1-5 of the drawings, the electro acoustic transducer device there shown generally comprises a standard or conventional type electricall; operated horn including diaphragm loudspeaker unit I, an air chamber structure 2, which embodies an air chamber 2 having rotatably mounted therein a thin, flat, rectangularly-shaped blade-like rotor element 3 of plastic material or the like, that is arranged tobe continuously revolved like a fan by a conventional electric motor 4, a second blade-like element 5 that is similar to the element 4, but is turnably mounted for circular adjustment in the air chamber 2 to thereby serve as a door or shutter that can be selectively turned from one position to another by a finger knob 6 in establishing an opening of a certain order at the front end of the air chamber 2 The air chamber structure 2 comprises a wall formation 2 v that is made of a suitable material, such as wood, and said wall formation has a generally rectangular tubular configuration that is open at both ends.

The front end of the loudspeaker unit 1 is provided with a flange 1 that is secured to the rear end of the air chamber wall formation 2* by screws or other fastening means indicated by the reference numeral 7.

The rotor element 3 is mounted for continuously revolving motion in the air chamber 2 and the shutter element 5 is mounted in said air chamber so as to be manually turnable and selectively positionable as previously indicated. For this purpose, bifurcated stud shafts 3 and 3 are fixedly secured centrally at the outer ends of the rotor element 3 and similar stud shafts 5 and 5 are fixedly secured centrally at the outer ends of the shutter element 5. The stud shafts 3 3 5 and 5 are secured to the respective elements 3 and 5, by suitable means, such as by screws 8, which extend through the bifurcated ends of the stud shafts and through the respective elements 3 and 5, as clearly indicated in FIG. 4. The stud shafts 3 3 5 and 5 all extend through similar separate bearing members 9 (see FIG. 4) that are fixedly secured in the wall formation 2 of the air chamber structure 2.

As will be clear from FIGS. 4 and 5, the rotor element 3 and the shutter element 5 are of lesser lengthwise and Widthwise dimension than the similar cross-sectional dimensions of the air chamber 2, so as to provide for unobstructed free rotational movement of the rotor element 3 and similar unobstructed free turning movement of the shutter element 5. To maintain the rotor element 3 properly positioned against axial movement in the air chamber 2*, the stud shafts 3 and 3' thereof have fixedly secured thereto positioning collars 3 and 3 the inner surfaces of which are arranged in lightly abutting relation with the adjacent outer surface portions of the air chamber wall formation 2 The shutter element 5 is similarly maintained against axial shifting movement by a fixedly attached collar 5 and the fixedly attached hub of the finger turning knob 6.

The stud shaft 3 has fixedly secured to its outer end a pulley 10, about which is trained a belt 11 that is driven by the electric motor 4 through a motor pulley 12. The motor 4 is mounted on a supporting bracket 13 secured to the outside of the wall formation 2 of the air chamber structure 2.

The diaphragm loudspeaker unit 1 is connected by two conductors 14 and 15, through a conventional switch or electronic organ stop (not shown) to the tone producing circuit of an electronic organ system which preferably, but not necessarily, would normally produce an acoustic output that would be musically classified as a string or reed tone.

The motor 4 is connected by two conductors 17 and 18, through a standard type of electronic organ stop, or electrical switch (not shown), to the power system of the electronic organ which will provide the proper electrical motor operating energy.

Operation When the diaphragm loudspeaker unit 1 and the motor 4 are switched on by the player of the electronic organ, the revolving motor element 3 in the air chamber 2 will impart a tremolo efiect characteristic to the tone emitted from the horn of the unit 1. To attain the desired quality and degree of such effect, the speed of the motor 4 is preferably set to revolve the rotor element 3 at a constant rate of speed of 3 revolutions per second. In this manner, the rotor element 3 will effectively vary the volume of air in the air chamber 2 so as to disturb the sound emitted from the horn of the loudspeaker unit 1 in the desired manner and to the desired degree. For further information concerning the principle of operation here involved, reference may be had to a book on this subject entitled Acoustical Engineering by Harry F. Olson, which was published July 3, 1957, by D. Van

'Nostrand of Princeton, New Jersey.

By selectively manually setting the shutter element 5, so as to provide an opening of a certain order at the front end of the air chamber 2*, the said quality and degree of tremolo sound eifect produced as indicated, will be modulated, varied, or transformed into a sound effect having substantially all the special qualities and characteristics of the vox humana stop of a pipe organ. I have found in practice that this vox humana sound or tone effect will result when the shutter element 5 is turned so that the opening at the front of the air chamber 2 is in the order of about one percent of the entire cross-sectional area of the front end opening of the air chamber. Since this adjustment is determined by ear, it will be understood that the indicated setting is subject to variation within the range of the special vox humana sound or tone effects attainable with my device and the one selected as best by a particular organist.

In accordance with actual tests conducted and comparisons made, it has been established that the vox humana results attained by the substitution of my electro acoustic transducer device, when cooperatively associated with an electronic organ system, are considered by professional or expert organists to constitute an entirely acceptable and satisfactory equivalent of one for the other.

Modifications The electro acoustic transducer device of my invention may also be provided in a form which will produce at one time the said special vox humana sounds or tones and at another time a muted sound eifect that is similar to the sound effect produced by a trumpet player when moving a derby toward and away from the end of his trumpet. Such form of my device is disclosed by FIG. 6. The device there shown includes all the parts and elements of FIGS. 1-5 previously described and to avoid redundancy of descriptive matter thereof such parts and elements are identified in FIG. 6 by corresponding reference characters with the exponent as added thereto for purposes of differentiation.

The device of FIG. 6 mainly differs from that illustrated by FIGS. 1-5, in that the device of FIG. 6 has added thereto or combined therewith a muting arrangement which generally comprises an electrical three phase servo motor 20, that is directly connected with the stud shaft 3, a three phase foot pedal operated positioning potentiometer 21 of standard design and construction, that is suitably located at the electronic organ console indicated by the letter C, a switch 22 which is mounted at the console C and is arranged so that when closed it will effect continuous rotation of the motor 4*, as previously described, and a switch 23 which is also mounted at the console C and is arranged so that, when the switch 22 is opened and the switch 23 is closed, the potentiometer 21 will control the servo motor 20 and the extent of depression of the foot pedal of the potentiometer 21 will determine the extent of rotary movement of the rotor element 3 in successive steps selectively and as desired by the organist through any angular extent of its forward and backward motion within the air chamber 2. In other words, the successive step by step forward and backward movements of the rotor element 3 will cause the latter to function as a shutter that can be operated at will by the organist in selective manner by the extent of depression of the foot pedal of the potentiometer 21. The servo motor 20 is connected in usual manner with the potentiometer 21 by three conductors 24, 25 and 26. The switch 23 is connected with the servo motor 20 and power lines A and B by conductors 27, 28 and 29. The switch 22 is connected with motor 4* and the power lines A and B by conductors 30, 31 and 32.

Let it be assumed that the shutter element 5 has been manually moved, for example, to substantially its vertical or fully closed position. Then, when the switch 23 is closed and the switch 22 is opened, the rotor element 3 will rotate only as selectively determined by the step by step depression of the foot pedal of the potentiometer 21. In this manner, the sound or tone effects which are emitted from the horn of the loudspeaker unit 1 are muted by the closed shutter element 5 and the organist, by selective step by step operation of the foot pedal of the potentiometer 21, can then further modify the said muted sound or tone efiects in substantially the same manner as when a trumpet player moves a derby, selectively and at will, toward and away from the end of his trumpet during the playing of the latter.

Of course, it will be apparent to those skilled in this art, that the two forms of the electro acoustic transducer device herein specifically shown and described, can be changed and modified in various ways Without departing from my invention, the scope of which is more particularly indicated and defined by the hereto appended claims.

I claim:

1. An electro acoustic transducer device comprising, a loudspeaker, a chamber structure arranged at the sound discharge end of the loudspeaker which chamber is provided with a sound emitting opening; and two similar elements rotatably mounted in relatively spaced relationship within said chamber, one of which elements is operatively arranged to effect agitation of the air within the chamber, and the other one of which elements is operatively arranged to effect variation of said sound emitting opening.

2. An electro acoustic transducer device in accordance with claim 1, wherein the two similar elements are substantially the same in size and configuration.

3. An electro acoustic transducer device in accordance with claim 1, wherein the two similar elements are in the form of substantially rectangular vanes.

4. An electro acoustic transducer device in accordance with claim 1, which includes power means for effecting rotary movement of one of said two similar elements.

5. An electro acoustic transducer device in accordance with claim 1, which includes a manually operable member for efiecting actuation of one of said two similar elements.

6. An electro acoustic transducer device in accordance with claim 1, which includes power means for effecting rotary movement of one of said two similar elements, and a manually operable member for effecting actuation of the other one of said two similar elements.

7. An electro acoustic transducer device in accordance with claim 1, wherein the said chamber structure is of a substantially rectangular tubular configuration.

8. An electro acoustic transducer device in accordance with claim 1, wherein said loudspeaker is of the horn including type.

9. An electro acoustic transducer device in accordance with claim 1, wherein the element that is operatively arranged to effect variation of said sound emitting opening has a rotatable movement range of at least degrees.

10. An electro acoustic transducer device in accordance with claim 1, which includes two separate motors for effecting rotary movement of one of said two similar elements.

11. An electro acoustic transducer device in accordance with claim 1, which includes two separate motors for effecting rotary movement of one of said two similar elements, and control means for selectively operating one or the other of said motors.

12. An electro acoustic transducer device in accordance with claim 1, which includes two separate motors for effecting rotary movement of one of said two similar elements, one of which motors is a servo motor that is arranged to effect intermittent rotary movement of said one element from one position to another.

13. An electro acoustic transducer device in accordance with claim 1, which includes two separate motors for effecting rotary movement of one of said two similar elements, one of which motors is a servo motor that is arranged to effect intermittent rotary movement of said one element from one position to another, and the other one of which motors is arranged to effect continuous rotation of said one element in one direction.

References Cited in the file of this patent UNITED STATES PATENTS 1,477,553 Grissinger Dec. 18, 1923 2,062,515 Hoschke Dec. 1, 1936 2,114,680 Goldsmith Apr. 19, 1938 2,412,212 Gerlat Dec. 10, 1946 2,780,302 George Feb. 5, 1957 2,847,081 Santi Aug. 12, 1958 

1. AN ELECTRO ACOUSTIC TRANSDUCER DEVICE COMPRISING, A LOUDSPEAKER, A CHAMBER STRUCTURE ARRANGED AT THE SOUND DISCHARGE END OF THE LOUDSPEAKER WHICH CHAMBER IS PROVIDED WITH A SOUND EMITTING OPENING; AND TWO SIMILAR ELEMENTS ROTATABLY MOUNTED IN RELATIVELY SPACED RELATIONSHIP WITHIN SAID CHAMBER, ONE OF WHICH ELEMENTS IS OPERATIVELY ARRANGED TO EFFECT AGITATION OF THE AIR WITHIN THE CHAMBER, AND THE OTHER ONE OF WHICH ELEMENTS IS OPERATIVELY ARRANGED TO EFFECT VARIATION OF SAID SOUND EMITTING OPENING. 